Missions are given by your Sponsor. Either he will send you a Pigeon Post requesting you to do a mission, or you can go to your sponsor and request for him to give you one. You can either reject the mission or accept it.
When you talk to your Sponsor regarding a mission, he will give you a hint on what the mission will be about. He will give you the names of the person you are to help and the directions to meet that person on the map.
